1. Field of the Invention
This invention relates to a machine for fitting and removing wheel tires for vehicles.
2. The Prior Art
As is known vehicle wheels include a metal rim having along the perimeter annular flanges adapted to house, as an adherent stop, the end portions, so-called “beads”, of an elastic tire.
The use is currently known of so-called “tire changing” machines for fitting and removing tires from and onto their relevant rims for carrying out maintenance, repair or replacement jobs.
Such tire changing machines comprise, generally, a frame adapted to support a clamping and rotating device for clamping and rotating the rim of a wheel onto/from which the tire must be fitted/removed and one or more tools for fitting and removing the tire.
Automatic tire changing machines are particularly known that include an operating head which has a tool for removing the tire and which is associated with the frame and vertically and horizontally movable by respective actuators.
The removal tool is arranged along a substantially transversal direction with respect to the longitudinal axis of the operating head, towards the wheel to be removed, and has a curved end part adapted to grip the tire bead.
In particular, the removal tool is turnable by means of a respective actuator around a horizontal axis between a bead clamping configuration in which it is tilted towards the wheel rim, a first configuration of entrainment of the tire edge in which it is arranged substantially vertical, and a second configuration of entrainment of the tire edge in which it is tilted in an opposite direction with respect to the wheel rim.
During the operating phase, an operator positions and blocks the wheel on the clamping and rotating device and, by means of a specific beading unit, performs a preliminary phase to detach the tire bead from the annular flanges of the rim. Subsequently, the operator regulates the position of the operating head with respect to the frame according to the specific dimensions of the wheel.
In particular, such regulation is done by moving the operating head upwards by means of a first actuator and horizontally by means of a second actuator.
The head is then lowered and the end part of the tool presses the side of the tire until it is inserted between the tire bead and the relevant flange on the rim.
The operation of a third actuator permits moving the tool to clamping configuration, in which the hooked extremity of the tool positions so as to withhold the tire bead.
Afterwards, the tool is positioned in the first withholding configuration and the operating head is raised so as to extract a portion of the bead above the rim.
To make it easier to extract the bead, the tool is positioned in the second withholding configuration by means of the third actuator and, at the same time, to prevent the tire for becoming too deformed, the operating head is moved horizontally and, by means of the second actuator, towards the rotation axis of the rim.
The rotation of the rim then allows the entire bead to come out of the respective flange.
These machines of known type are however susceptible to upgrading, in particular in order to ensure a correct and easy removal of the tire, while at the same time allowing a more simple structure and operation.
The need to control and combine several actuators during the removal phase in fact requires the presence of a processing unit suitable for coordinating operation, with consequent increase in the general complexity of the machine.
The main aim of the present invention is to provide a machine for fitting and removing wheel tires for vehicles that allows achieving the above-mentioned standards of upgrading.
Another object of the present invention is to provide a machine for fitting and removing wheel tires for vehicles that allows achieving the mentioned standards of upgrading of the state of the art within a rational solution that is easy and effective to use and of low cost.